A prior art for the device-transfer mechanism for an IC test handler system is described by referring to FIGS. 6, 7, and 8. This system is comprised of a supply buffer section 40, a thermal insulation wall 54, a soak chamber 110, a rotational arm 120, a measurement section 70, a storage buffer section 50, and a transfer mechanism of multiple boats 100. As a transfer-drive method, drive sources such as a pulse motor and a servo motor, and a combination of belts, gears and a rotation-screw mechanism are used for this purpose.
A suction section for IC devices 71 is arranged at the tip of a rotation arm 120 as shown in FIG. 8, and is comprised of a suction pad 82, which sucks the IC device 71, a suction arm 80 and an up/down drive mechanism 84. An air regulating pressure 83, of vacuum pressure/atmospheric pressure from an ejector for an external suction control is connected to the suction arm 80 and is supplied to the suction pad 82. The device 71 is sucked and released by air pressure in the suction pad 82. The up/down drive mechanism 84 using a cylinder or a solenoid and driven by a control signal 85, transfers the device 71 in the up and down strokes.
Inside the thermal shield wall 54 is a constant-temperature chamber having a structure of thermal insulation for heating and cooling the device to set to a desired temperature until the device is measured at the measurement section 70. In order to maintain the device to be measured at the constant temperature, it is required that the device be kept inside the constant temperature chamber for more than a preset period. Hence, the soak chamber is designed to provide this preset period. Inside the thermal insulation wall 54, a structure is arranged so that boats 100 can pass through for supplying and storing devices.
Here, the time duration between the time when the device is placed in the constant-temperature chamber and the time when the device reaches a constant temperature is called a "soak time." Also, the time between the completion of device electrical testing and the start of the next device testing is called an "index time." The time between the start and end of the device electrical testing is called a "test time." Also, the total of the index time and test time is called a "cycle time." Also, the duration of the device test time from the time the device is taken out from the supply tray and the time the device is placed in the storage tray is called an "output time."
Transfer of the device 71 is performed by a mechanism including the boats. A pocket 13 that carries one or several devices is disposed on the boat 100, moved and transferred by a unit of the boat. The boat carrier mechanism is disposed to move the boats 100 by rotation, and each path for the boats 100 has a transfer mechanism. The path starts at a supply buffer section 40, and its route runs through paths 201, 205, 206, 207, 208 and is returned.
A plurality of boats 100 whose pockets are shaped according to the device configurations (DIP, SOP, QFP, etc.) to be carried, can be readily replaced with other boats even when the device configuration is changed. The supply buffer section 40 is comprised of a supply y-arm 41, a supply x-arm 42, and a supply tray 43. A suction section 45 is set at the tip of the supply y-arm 41. The transfer operation is, first to move the supply y-arm 41 and the supply x-arm 42 to pick up a device by a suction force from above the supply tray 43, then to carry the device to the pocket position of the boat 100 at the position 200 and to release and drop the device. The operation is repeated for every supply timing.
The device 71 on the boat 100 at the position 200 is carried to a soak chamber 110 through the path 201 by a horizontal transfer mechanism after passing through the thermal shield wall 54. The soak chamber 110 is a buffer used to provide time, i.e., the soak time, for heating and cooling the devices 71 to a preset temperature in the constant-temperature chamber. This soak chamber has many boats 100 inside the chamber in order not to reduce the index time of the IC handler. The boat 100 carried to the soak chamber 110 moves up through the path 202 one by one as shown in FIG. 7, moves to the adjacent path 203, moves down the path 204, and reaches the suction section 121a of the supply arm position of a rotation arm 120 on the path 205.
There are four arms on the rotation arm 120. Suction sections 121a, 121b, 121c, and 121d are disposed at the tips of each arm. The first arm at the supply position of the rotation arm 120 drives the suction section 121a down and by a suction force picks up the device 71 positioned at the pocket on the boat 100, then moves up. A device 71 at the second arm of the rotation arm 120 is simply a standby device.
The third arm at the measurement position of the rotation arm 120 moves down a device 71 at the suction section 121c, places the device 71 on the contacts of the measurement section 70, where the electrical testing is proceeded. The third arm brings up the device by suction after completing the electrical testing, then moves upward. Here, in the measurement section 70, leads of the device 71 received from the rotation arm 120 makes contact with electrodes for electrical testing and measurements for various electrical tests are performed.
The fourth arm of the rotation arm 120 at the storage position lowers the device 71 at the suction section 121d and drops it in the pocket of the boat 100. This boat 100 is empty after having passed through the paths 205 and 206. The above noted four arms are rotational-type transfer mechanisms that perform suction of the devices to be measured or the measured devices, device measurements, and ejection of the device after measurements all at once, rotating for every cycle and moving to the next process.
The boat 100 at the suction section 121d where a device 71 is riding after measurements reaches the position 210 of the storage y-arm 51 by transfer on the path 207. The storage buffer section 50 comprises a storage y-arm 51, a storage x-arm 52, and a storage tray 53. A suction section 55 is arranged at the tip of the storage y-arm 51. The transfer operation is used to transfer the storage y-arm 51 and storage x-arm 52 after lifting the device by suction at the position 210 using the suction section 55, and to drop the device 100 in the pocket of the storage tray 53 after carrying the device 100 to a predetermined position of the storage tray 53. This storage operation is repeated.
As described above, in the prior art device transfer mechanism, the structure of the soak chamber 110 is complex because of too many transfer processes. Further, because of so many transfer-drive devices, the cost of the mechanism is very high. Moreover, the soak chamber 110 requires a large installation space and a large constant-temperature chamber, which is not desirable.
In addition, in the prior art, the transfer processes of boats 100 increase because the devices are moved by riding on the boat 100, which results in unnecessary mechanisms, and it is not necessarily an adequate structure for the handler, which is required to be durable and reliable. Also, one of the four arms of the rotation arm 120 is not used, which increases the cost for its suction section.
In addition, a mechanism for changing the number of boats 100 to be stored in the soak chamber 110 is not readily changed. Therefore, it is designed to store many boats in order to secure the soak time even when the test time for the device is short. However, because of this arrangement, the optimum number of boats corresponding to different test times for various devices cannot be changed flexibly, and it may provide soak time more than required, and is not necessarily easy to operate.